This invention relates generally to a method for marking petroleum hydrocarbons with pyrazinoporphyrazine compounds for subsequent identification.
M. Matsuoka, in “NIR Dyes for Information Recording,” Near-Infrared Dyes for High Technology Applications (S. Daehne et al., eds.), pages 203–231 (Kluwer Academic Publishers, 1998), discloses pyrazinoporphyrazine compounds for use in solid optical information recording systems, e.g., recordable compact disks. This reference, however, does not suggest a method for marking petroleum hydrocarbons.
The problem addressed by this invention is to find a marker suitable for use in petroleum hydrocarbons.